Lab and analysis
InChI
Definition
The IUPAC International Chemical Identifier, an open text string that describes a chemical structure in layers.
InChI is an open standard maintained by IUPAC and the InChI Trust. It is generated by software from a structure and encodes it in layers: formula, connectivity, hydrogens, charge, stereochemistry and isotopes. Because the algorithm is public, anyone can generate the same InChI for the same structure.
Ethanol's standard InChI is InChI=1S/C2H6O/c1-2-3/h3H,2H2,1H3. InChI strings can be long, so databases usually index the shorter InChIKey.
Related terms
- CAS registry number (CAS RN)A unique numeric identifier assigned by the Chemical Abstracts Service to a chemical substance, such as 7732-18-5 for water.
- InChIKeyA fixed length 27 character hashed form of the InChI, used to search and link chemical records, for example LFQSCWFLJHTTHZ-UHFFFAOYSA-N for ethanol.
- SMILESA line notation that writes a chemical structure as a short text string, such as CCO for ethanol.
- IUPAC nameThe systematic name of a chemical built by the nomenclature rules of the International Union of Pure and Applied Chemistry.